This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To compare treatment success (defined as the probability of not experiencing virologic failure or discontinuation of NRTI strategy by week 48) between subjects taking a new regimen of more than two active agents (defined by a cPSS >2.0) that includes versus excludes NRTIs.